PZEV exhaust gas recirculation valve with activated carbon

Abstract

An exhaust gas recirculation valve includes a body including a passageway extending between an inlet and an outlet. The passageway communicates a flow of the exhaust gases. A bearing, disposed in the body, has a bearing passageway. A valve member is located in the passageway between the inlet and outlet and has a portion movably disposed in the bearing passageway such that a clearance path is defined between the portion of the valve member and the bearing. The clearance path is in communication with atmosphere through openings in the body. The valve member is constructed and arranged to regulate the flow of the exhaust gases. Activated carbon is associated with a portion of the body so as to adsorb hydrocarbons associated with the clearance path and thus prevent hydrocarbons from escaping to the atmosphere through the openings in the body.

1. An exhaust gas recirculation valve for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine, the valve comprising:
 a body including a passageway extending between an inlet and an outlet, the passageway communicating a flow of the exhaust gases; 
 a bearing disposed in the body, the bearing having a bearing passageway, 
 a valve member located in the passageway between the inlet and outlet, the valve member having a portion movably disposed in the bearing passageway such that a clearance path is defined between the portion of the valve member and the bearing, the clearance path being in communication with atmosphere through openings in the body, the valve member being constructed and arranged to regulate the flow of the exhaust gases; and 
 activated carbon associated with a portion of the body so as to adsorb hydrocarbons associated with the clearance path and thus prevent hydrocarbons from escaping to the atmosphere through the openings in the body, 
 wherein the activated carbon one of covers surfaces defining the openings or is disposed within the openings. 
 
   
   
     2. The valve of  claim 1 , wherein the portion of the body is a cap constructed and arranged to be coupled to an electric vacuum regulator (EVR). 
   
   
     3. The valve of  claim 2 , wherein the activated carbon is activated charcoal in one of a cloth substrate form, a pellet form, a granular form, or a puck form. 
   
   
     4. The valve of  claim 3 , wherein the activated charcoal is constructed and arranged to adsorb hydrocarbons associated with the clearance path and during engine-off cycles and desorb hydrocarbons during engine drive cycles. 
   
   
     5. The valve of  claim 2 , wherein the openings are defined in a bottom surface of the cap and activated carbon is a cloth substrate form substantially covering the bottom surface of the cap, thus covering the opening. 
   
   
     6. The valve of  claim 1 , further comprising a diaphragm having a first portion fixed to the portion of the valve member, a second portion fixed with respect to the body, and a flexible portion connecting the first and second portions. 
   
   
     7. The valve of  claim 6 , wherein the body includes a cap and the diaphragm is clamped between the cap and an upper body. 
   
   
     8. The valve of  claim 7 , wherein the diaphragm and the upper body define a chamber adapted to be in fluid communication with a supply of vacuum in the intake manifold. 
   
   
     9. The valve of  claim 8 , in combination with an electric vacuum regulator valve regulating the supply of vacuum to the chamber. 
   
   
     10. The combination of  claim 9 , further in combination with a differential pressure sensor constructed and arranged measure pressure associated with the outlet. 
   
   
     11. An exhaust gas recirculation valve for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine, the valve comprising:
 a body including a passageway extending between an inlet and an outlet, the passageway communicating a flow of the exhaust gases; 
 a bearing disposed in the body, the bearing having a bearing passageway, 
 a valve member located in the passageway between the inlet and outlet, the valve member having a portion movably disposed in the bearing passageway such that a clearance path is defined between the portion of the valve member and the bearing, the clearance path being in communication with atmosphere through openings in the body, the valve member being constructed and arranged to regulate the flow of the exhaust gases; and 
 means, associated with a portion of the body, for adsorbing hydrocarbons associated with the clearance path and thus prevent hydrocarbons from escaping to the atmosphere through the openings in the body, 
 wherein the means for adsorbing one of covers surfaces defining the opening or is disposed within the openings. 
 
   
   
     12. The valve of  claim 11 , wherein the portion of the body is a cap constructed and arranged to be coupled to an electric vacuum regulator (EVR). 
   
   
     13. The valve of  claim 11 , wherein the means for adsorbing is constructed and arranged to adsorb hydrocarbons associated with the clearance path and during engine-off cycles and desorb hydrocarbons during engine drive cycles. 
   
   
     14. The valve of  claim 13 , wherein the means for adsorbing is activated charcoal in one of a cloth substrate form, a pellet form, a granular form, or a puck form. 
   
   
     15. The valve of  claim 14 , wherein the openings are defined in a bottom surface of the cap and activated charcoal is a cloth substrate form substantially covering the bottom surface of cap, thus covering the openings. 
   
   
     16. A method of preventing hydrocarbons in an exhaust gas recirculation valve from escaping to atmosphere, the method comprising:
 providing an exhaust gas recirculation valve for recirculating exhaust gases from an internal combustion engine to an intake manifold of the internal combustion engine, the valve including a leak passage permitting hydrocarbons to leak to atmosphere, and 
 providing activated carbon to one of cover surfaces defining the leak passage or be disposed within the leak passage to adsorb hydrocarbons and prevent the hydrocarbons from leaking to atmosphere. 
 
   
   
     17. The method of  claim 16 , wherein the step of providing the valve provides a valve comprising:
 a body including a passageway extending between an inlet and an outlet, the passageway communicating a flow of the exhaust gases; 
 a bearing disposed in the body, the bearing having a bearing passageway, and 
 a valve member located in the passageway between the inlet and outlet, the valve member being constructed and arranged to regulate the flow of the exhaust gases, the valve member having a portion movably disposed in the bearing passageway such that a clearance path is defined between the portion of the valve member and the bearing, the clearance path being in communication with atmosphere through openings in the body, the openings defining the leak passage. 
 
   
   
     18. The method of  claim 17 , wherein the body includes a cap, the openings are defined in the bottom surface of the cap and activated carbon is a cloth substrate form substantially covering the bottom surface the cap, thus covering the openings. 
   
   
     19. The method of  claim 17 , wherein the activated carbon is activated charcoal in one of a cloth substrate form, a pellet form, a granular form, or a puck form. 
   
   
     20. The method of  claim 17 , wherein the activated carbon is constructed and arranged to adsorb hydrocarbons associated with the leak passage during engine-off cycles and desorb hydrocarbons during engine drive cycles.